<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1 {
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*margin-left: 100px;*/
            /*margin-top: 100px;*/
            /*margin-bottom: 100px; !*向下顶开100px *!*/
            margin: 50px;
            /*上下50 左右100*/
            margin: 50px 100px;
            /*顺时针赋值*/
            margin: 10px 20px 30px 40px;
        }

        #d2 {
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*上下相邻彼此添加外边距取最大值
            margin-top: 100px;*/
        }
        #s1{
            margin-right: 100px;
        }
        #s2{
            /*行内元素左右相邻彼此添加外边距 两者相加  */
            margin-left: 50px;
        }
        #big{
            width: 200px;
            height: 200px;
            background-color: green;
            /*解决粘连问题*/
            overflow: hidden;
        }
        #big>div{
            width: 50px;
            height: 50px;
            background-color: red;
            margin-left: 50px;
            margin-top: 50px;
        }
        #border-div{
            width: 200px;
            height: 200px;
            border: 1px solid blue;
            border-radius: 100px;
        }
    </style>
</head>
<body>
<div id="border-div"></div>
<div id="big">
    <div></div>
</div>
<div id="d1">外边距测试</div>
<div id="d2">div2</div>
<span id="s1">span1</span>
<span id="s2">span2</span>
</body>
</html>